OLYMPIA, Washington - A Washington state man was arrested by federal agents on Tuesday after making threats against President Barack Obama in emails sent to the FBI, authorities said.

The FBI had notified the Secret Service that it had received "alarming" emails from an individual regarding the president, Secret Service spokesman Brian Leary told Reuters.

The Secret Service identified that man as Anton Caluori, 31.

Secret Service agents accompanied Federal Way police officers to Caluori's home south of Seattle on Tuesday, where they encountered the suspect brandishing a shotgun, Leary said.

When Caluori was taken into custody, he spoke to officers about using explosive devices. Bomb squad officers searched the man's home but found no evidence of explosives, Leary said.

Caluori was charged with threatening the president and assault of a federal agent, according to Federal Way spokeswoman Cathy Schrock.

He is due to appear in a federal court on Wednesday at 2 pm (21:00 GMT), Leary said.